[Danny T]

It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Any thoughts on this ?

[Mike Rivers]

Danny T wrote:
It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

Exactly what specification are you looking at? Can you find
one and either quote it exactly or paste it into a message?
It seems odd that a headphone amplifier should "need at
least 100 ohms."

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

You'll probably find that there's a substantial volume
difference between the two at the same volume setting on the
amplifier. Assuming that efficiency is about the same for
similar styles of phones, the more watts you have, the
louder. For a given voltage going to the headphones,
assuming there's sufficient current available, the lower the
impedance, the more watts.

Since many portable devices (MP3 players for example)
operate on a pretty low voltage, well below the maximum 30v
swing (+/- 15v) typical of op amp devices, headphones
designed for such low voltage devices are made with lower
impedance to get up to the desired ear splitting volume. A
headphone amplifier that's powered by someting more than a
couple of AA cells can put out a higher voltage, but may
limit the current for ear safety if nothing else, so for the
same volume as you get from your MP3 player, you may want a
higher impedance headphone for your stand-alone amplifier.



--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

[Danny T]

Exactly what specification are you looking at? Can you find
one and either quote it exactly or paste it into a message?
It seems odd that a headphone amplifier should "need at
least 100 ohms."

The one manual I had sitting around reads about the same as I remember
the others to and it does say not to fall below 100 ohms. So if the
Sony's are only 63, that would mean I could not use them according to
their specs, right? On the other hand, if I have that backwards, then
the AKG K240's cant be used because they have 600 ohms printed on the
side of them.

I'm thinking at such a low voltage, like you said, the volume would be
the only real short term thing to think about. The long term affect
would probably be to immaturely age the product.

I never really looked at headphone impedance before but on the casual
accidental noticing of it found that the impedance of must of them are
rather high.

I understand ohm's law but I guess I'm confused about the way they
have the limits based for the amps. If you need at least 100 ohms -
and for instance, the Behringer powerplay has room for three
headphones per each of the amps in the rack, you'd need at least 300
ohms on each headset or you'd drop to low and start burning the thing.
It seems a rather dishonest way of promoting the thing.

[[email protected]]

On Sun, 23 May 2010 16:20:10 -0700 (PDT), Danny T wrote:


Exactly what specification are you looking at? Can you find
one and either quote it exactly or paste it into a message?
It seems odd that a headphone amplifier should "need at
least 100 ohms."

The one manual I had sitting around reads about the same as I remember
the others to and it does say not to fall below 100 ohms. So if the
Sony's are only 63, that would mean I could not use them according to
their specs, right? On the other hand, if I have that backwards, then
the AKG K240's cant be used because they have 600 ohms printed on the
side of them.

I'm thinking at such a low voltage, like you said, the volume would be
the only real short term thing to think about. The long term affect
would probably be to immaturely age the product.

I never really looked at headphone impedance before but on the casual
accidental noticing of it found that the impedance of must of them are
rather high.

I understand ohm's law but I guess I'm confused about the way they
have the limits based for the amps. If you need at least 100 ohms -
and for instance, the Behringer powerplay has room for three
headphones per each of the amps in the rack, you'd need at least 300
ohms on each headset or you'd drop to low and start burning the thing.
It seems a rather dishonest way of promoting the thing.

Some of the headphone amps I have looked at are simply op-amps driving the
output through a series resistor...

If you place a load that is too low you will simply lose too much signal inside
the amp, and get distortion. I doubt you can burn the headphone amp, they should
be designed to take a short circuit either because of the series resistor or
internal limiting. Some amps have a complementary pair to increase the drive
capacity, and some use a power amp chip. These types usually can go below 100
ohms...

Knowing the circuit you have is the most important consideration here...

[Mike Rivers]

Danny T wrote:

The one manual I had sitting around reads about the same as I remember
the others to and it does say not to fall below 100 ohms. So if the
Sony's are only 63, that would mean I could not use them according to
their specs, right?

Well, what are you afraid of if you plug them in? That the
amplifier will fill the room with smoke? That you'll get
cancer of the earlobes? Or the most serious of all - that
you'll void the warranty? Naw, it only means that you'll
get distortion if you turn it up all the way. If you can
stand to listen to it, you can.

I never really looked at headphone impedance before but on the casual
accidental noticing of it found that the impedance of must of them are
rather high.

Neither did anyone else when a headphone jack was connected
to the output of a power amplifier (15 to 250 watts)
isolated with a couple of resistors, and you adjusted the
amplifier's volume control for a comfortable (or
uncomfortable) listening level. It was only when low
voltage/power devices came into our lives that headphone
drive current became a real consideration.

I understand ohm's law but I guess I'm confused about the way they
have the limits based for the amps.

There are hard limits, and there are recommendations.
There's also the consideration of liability if someone
damages his hearing by using headphones that are too loud
when connected to a particular device. Amplifiers generally
are current-limited because sometimes output cables fail and
short-circuit the output. The worst that can happen is that
at one end of the impedance scale, the headphones won't get
very loud at all, and at the other end of the scale, they'll
distort before they get loud enough. So it's more a matter
of customer perception and satisfaction rather than
electrical hazard.

If you need at least 100 ohms -
and for instance, the Behringer powerplay has room for three
headphones per each of the amps in the rack, you'd need at least 300
ohms on each headset or you'd drop to low and start burning the thing.

If it were really designed like that, it would be a bad
design. When you have multiple output jacks from the same
amplifer, there's enough resistance in series between the
amplifier output and the jack so that the amplifier never
sees a lower impedance than that series resistor. This both
protects the amplifier from too much load on its output and
also means that plugging in a second or third set of
headphones doesn't significantly affect the listening volume
of the other headphones.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

[Arny Krueger]

"Danny T" wrote in message


It seems to me that most headphone amps need at least 100
ohms - I have 3 and they are rated at no less then 100
ohms....

Headphone amps are like speaker amps in that thelowest load impedances they
specify are usually minimums.

I know of a ton of headphone amps that are rated for less than 100 ohms.

My first guess: http://www.rane.com/pdf/hc4sdat.pdf - "drives 32-600 ohm"

My second guess: http://www.behringer.com/EN/Products/HA4700.aspx -
"Minimum output load impedance 8 ohms".

My third guess: http://www.mackie.com/products/hm54/pdf/HM54_OM.pdf
"Maximum Rated Output (1 kHz): 100 mW ±0.5 dB @ 1% THD (60? load, all
channels driven) "

[Scott Dorsey]

Danny T wrote:
It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

That's fine.

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

That's fine too. I'm not sure what the issue is.

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Those are headphones intended for use with 600 ohm sources, which were a
lot more common than they are now. It's harder to make a good high-Z headphone
because of the mass of the coil, and of course crappy battery-powered gear
can't swing a lot of voltage into headphones, so they are less popular.

Any thoughts on this ?

You worry too much. A decent headphone amp should be able to drive a wide
variety of different loads. If you're paralleling 20 headphones off of one
amp, you will do better to use high-Z phones.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Danny T]

On May 24, 10:09*am, (Scott Dorsey) wrote:
Danny T wrote:

It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

That's fine.

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

That's fine too. *I'm not sure what the issue is.

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Those are headphones intended for use with 600 ohm sources, which were a
lot more common than they are now. *It's harder to make a good high-Z headphone
because of the mass of the coil, and of course crappy battery-powered gear
can't swing a lot of voltage into headphones, so they are less popular.

Any thoughts on this ?

You worry too much. *A decent headphone amp should be able to drive a wide
variety of different loads. *If you're paralleling 20 headphones off of one
amp, you will do better to use high-Z phones.
--scott
--
"C'est un Nagra. *C'est suisse, et tres, tres precis."

Hey Scott, I'm not actually worried about anything - frankly, this
stuff is cheap and I've spent more on a night's worth of beer :-) I
just had some questions about why because things didn't add up right
in my head. I started thinking about how specs were written and didn't
want to believe that companies would stretch things like they do.

The unit I just plugged into my board is a behringer powerplay pro
that has some cool looking features. I actually bought 3 or 4 of these
years back and lost them somewhere. Anyway, I just found this one,
never opened and thought what the hell. I didn't even know I had it
until a few days ago. I doubt I paid more then 100 for it.

When something comes up that I don't know I figure its a good time to
ask and learn.

Thanks for the help

[Meindert Sprang]

"Soundhaspriority" wrote in message
...
...some of them couple to the output through a resistor, which they do
because
it actually flattens the output of a small op-amp.

I think the main reason of doing that is to make the output short-circuit
proof. Adding a resistor lowers the damping factor and you don't want that
for a nice tight bass response.

As to whether there actually exists a low impedance headphone amp, I do
not know.

Well, the ones I used to build had one. Less than one Ohm.

Meindert

[Ben Bradley[_2_]]

On Mon, 24 May 2010 11:07:41 -0700 (PDT), Danny T
wrote:

On May 24, 10:09*am, (Scott Dorsey) wrote:
Danny T wrote:

It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

That's fine.

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

That's fine too. *I'm not sure what the issue is.

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Those are headphones intended for use with 600 ohm sources, which were a
lot more common than they are now. *It's harder to make a good high-Z headphone
because of the mass of the coil, and of course crappy battery-powered gear
can't swing a lot of voltage into headphones, so they are less popular.

Any thoughts on this ?

You worry too much. *A decent headphone amp should be able to drive a wide
variety of different loads. *If you're paralleling 20 headphones off of one
amp, you will do better to use high-Z phones.

Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.


--scott
--
"C'est un Nagra. *C'est suisse, et tres, tres precis."

Hey Scott, I'm not actually worried about anything - frankly, this
stuff is cheap and I've spent more on a night's worth of beer :-) I

I found I can afford better gear since I quit drinking!

just had some questions about why because things didn't add up right
in my head. I started thinking about how specs were written and didn't
want to believe that companies would stretch things like they do.

The unit I just plugged into my board is a behringer powerplay pro
that has some cool looking features. I actually bought 3 or 4 of these
years back and lost them somewhere. Anyway, I just found this one,
never opened and thought what the hell. I didn't even know I had it
until a few days ago. I doubt I paid more then 100 for it.

I googled, that must be the 4-channel version. There's an 8-channel
Behringer for around $150.


When something comes up that I don't know I figure its a good time to
ask and learn.

There's my post here on the 7506 from a few years ago:

http://groups.google.com/group/rec.a...75dacad28b2e55

Do you have a schematic for the headphone amp? The REAL specs
depend on things such as the circuit's power voltage (total difference
between the most positive and most negative rails), and any resistance
between the active device's output and the headphone jack. The max
headphone volume depends on the headphone's sensitivity (rated as
dBSPL level into the ear with a certain amount of POWER into the
headphone), and the max voltage the amp can provide (in RMS - 0.7
times the peak), the impedance of the headphone, and any resistance in
series with the amp (whatever might be between the internal active
device and the headphone jack). That involves the power formula
(P=I*E) as well as Ohm's law, and a little algebra to combine them.
With all that you can calculate the max SPL the headphone amp can
drive a specific model of headphones.

As for my earlier post I linked to, the 7506's need a very low
impedance driving them to get rid of that big bad resonance at 5k or
whatever it is. It's just like power amps and speakers - the larger
damping factor of the amp (translates to lower impedance of the amp),
the better it electrically damps and "controls" the speaker.


Thanks for the help

[Danny T]

On May 26, 3:17*pm, Ben Bradley wrote:
On Mon, 24 May 2010 11:07:41 -0700 (PDT), Danny T





wrote:
On May 24, 10:09*am, (Scott Dorsey) wrote:
Danny T wrote:

It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

That's fine.

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

That's fine too. *I'm not sure what the issue is.

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Those are headphones intended for use with 600 ohm sources, which were a
lot more common than they are now. *It's harder to make a good high-Z headphone
because of the mass of the coil, and of course crappy battery-powered gear
can't swing a lot of voltage into headphones, so they are less popular..

Any thoughts on this ?

You worry too much. *A decent headphone amp should be able to drive a wide
variety of different loads. *If you're paralleling 20 headphones off of one
amp, you will do better to use high-Z phones.

* *Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

--scott
--
"C'est un Nagra. *C'est suisse, et tres, tres precis."

Hey Scott, I'm not actually worried about anything - frankly, this
stuff is cheap and I've spent more on a night's worth of beer :-) *I

* *I found I can afford better gear since I quit drinking!

just had some questions about why because things didn't add up right
in my head. I started thinking about how specs were written and didn't
want to believe that companies would stretch things like they do.

The unit I just plugged into my board is a behringer powerplay pro
that has some cool looking features. I actually bought 3 or 4 of these
years back and lost them somewhere. Anyway, I just found this one,
never opened and thought what the hell. I didn't even know I had it
until a few days ago. I doubt I paid more then 100 for it.

* *I googled, that must be the 4-channel version. There's an 8-channel
Behringer for around $150.



When something comes up that I don't know I figure its a good time to
ask and learn.

* *There's my post here on the 7506 from a few years ago:

http://groups.google.com/group/rec.a.../thread/885b06...

* *Do you have a schematic for the headphone amp? The REAL specs
depend on things such as the circuit's power voltage (total difference
between the most positive and most negative rails), and any resistance
between the active device's output and the headphone jack. The max
headphone volume depends on the headphone's sensitivity (rated as
dBSPL level into the ear with a certain amount of POWER into the
headphone), and the max voltage the amp can provide (in RMS - 0.7
times the peak), the impedance of the headphone, and any resistance in
series with the amp (whatever might be between the internal active
device and the headphone jack). That involves the power formula
(P=I*E) as well as Ohm's law, and a little algebra to combine them.
With all that you can calculate the max SPL the headphone amp can
drive a specific model of headphones.

* *As for my earlier post I linked to, the 7506's need a very low
impedance driving them to get rid of that big bad resonance at 5k or
whatever it is. It's just like power amps and speakers - the larger
damping factor of the amp (translates to lower impedance of the amp),
the better it electrically damps and "controls" the speaker.





Thanks for the help

I don't have anything but a little paper for instructions which I
think I probably through out.

The 7506 are not my favorite listening choice but I have found them to
not let much bleed through to the mic so for that reason I have
several hanging around. I've not noticed the stand out cowbell effect
you were talking about in your other post but I have noticed that my
high e string, played about a fret or two up and upward to about the 7
fret, and my b string from about my 3rd fret up can sound just
terrible. When I play things back through the speakers there is no
problem. I don't know why I didn't think of that before but obviously
the phones are punching up that freq on me. I kept thinking I was just
getting tracking fatigue. I'm going to have to try my k240's and see
of the tracks still sound bad to me.

I didn't even bother to think it could be the phones. I just figured I
was screwing up the take with a little fingernail touching the string
or something. (I've been doing a lot of finger style guitar) I might
owe you a beer here!

[Mike Rivers]

Ben Bradley wrote:

Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

[Danny T]

On May 26, 7:13*pm, Mike Rivers wrote:
Ben Bradley wrote:
* *Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

Somebody didn't get some last night

[[email protected]]

On Wed, 26 May 2010 20:13:32 -0400, Mike Rivers wrote:

Ben Bradley wrote:

Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

very funny...

My ex was a radio announcer at one time, and one day she came home with an ear
ache. Seems the asshole at the controls found a way to put 130db or so into her
phones for a few seconds, (till she ripped them off), making it some what
uncomfortable to finish her shift.

The industry needs limited head phone amplifiers. (not just volume controls.).

I for one refuse to 'try' other peoples headphones, they usually want to turn
them up loud.

[[email protected]]

On 2010-05-26 said:
There's already a device for that. It's called the volume
control.
very funny...
My ex was a radio announcer at one time, and one day she came home
with an ear ache. Seems the asshole at the controls found a way to
put 130db or so into her phones for a few seconds, (till she ripped
them off), making it some what uncomfortable to finish her shift.
The industry needs limited head phone amplifiers. (not just volume
controls.).

IF I'm feeding people other than myself program via
headphones or in-ear there's always limiters in the chain.
I won't be responsible for damaging somebody else's hearing
because of a screwup somewhere. YEs I'm going to be minding
the volume controls, but in a live situation I can't always
be sure something stupid might not occur.

I for one refuse to 'try' other peoples headphones, they usually
want to turn them up loud.

CAn understand that. I hate to use them even while working
ham radio on the hf bands because about the time I get a
comfortable listening level of a weak station some yokel
while dump in a carier enough off frequency that he gives me
1.5 khz or something else neat and the agc on my receiver
can't knock it down in time for it not to be painful. I'll
put 'em on if I"m trying to work a weak radio op aboard a
vessel at sea who might have an emergency or something like
that, but otherwise ...

My lady otoh won't run a net on hf without using them.





Richard webb,

replace anything before at with elspider
Remote audio in the Memphis, Tn. area: see www.gatasound.com

[Mike Rivers]

wrote:

The industry needs limited head phone amplifiers. (not just volume controls.).

I for one refuse to 'try' other peoples headphones, they usually want to turn
them up loud.

You're being smart. But you could turn the volume control
down before you put the headphones on. I won't deny that
excessive headphone volume has contributed to hearing loss,
however. There are campaigns that start at the elementary
school level warning of the dangers of listening too loud,
but like so many other things that try to protect us from
our own stupidity, people will find a way around it.

I remember that Sony at one point made a Walkman cassette
player that had a little red light that came on when the
volume was too high (calibrated to some SPL level with the
headphones that came with it). Of course the first thing
every kid who had one wanted to do was make that light come on.


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

[geoff]

Danny T wrote:
It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Any thoughts on this ?

The newer ones are all around 55 Ohms. Run a resistor ( two) in series and
turn the volume up to compensate.


geoff

[Ty Ford]

On Wed, 26 May 2010 20:28:28 -0400, Danny T wrote
(in article
):

On May 26, 7:13*pm, Mike Rivers wrote:
Ben Bradley wrote:
* *Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

Somebody didn't get some last night

Unwarranted, mean spirited and not to the point.

Ty Ford


--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demos http://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA

[Danny T]

On May 27, 8:09*am, Ty Ford wrote:
On Wed, 26 May 2010 20:28:28 -0400, Danny T wrote
(in article
):





On May 26, 7:13*pm, Mike Rivers wrote:
Ben Bradley wrote:
* *Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

Somebody didn't get some last night

Unwarranted, mean spirited and not to the point.

Ty Ford

--Audio Equipment Reviews Audio Production Services
Acting and Voiceover Demoshttp://www.tyford.com
Guitar player?:http://www.youtube.com/watch?v=yWaPRHMGhGA

Sorry - I was joking. That didn't read the way I meant to write it. I
would hope Mike knows I think very highly of him. I neglected to place
the traditional smilie face but the intent of smilie face was there -

[Danny T]

On May 26, 7:28*pm, Danny T wrote:
On May 26, 7:13*pm, Mike Rivers wrote:

Ben Bradley wrote:
* *Or a low-power amp meant for speakers. One goal here is to limit
the power into each headphone so the dBSPL at the ear stays below
immediate ear damage level.

There's already a device for that. It's called the volume
control.

--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

Somebody didn't get some last night

Sorry Mike -- I was joking. I neglected to place the traditional
smilie face but the intent of smilie face was there -

[Scott Dorsey]

Danny T wrote:

Hey Scott, I'm not actually worried about anything - frankly, this
stuff is cheap and I've spent more on a night's worth of beer :-) I
just had some questions about why because things didn't add up right
in my head. I started thinking about how specs were written and didn't
want to believe that companies would stretch things like they do.

Because companies make cheap junk. Everybody wants their headphones to be
more efficient and run off lower voltage rails, so they go to lower and
lower impedance. But everybody wants their output sections to cost less,
so they skimp on current drive.

The end result is that if you get a real headphone amp, your headphones will
probably have flatter response than if you plug them into the headphone output
of a bargain-basement mixer.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Laurence Payne[_2_]]

On Thu, 27 May 2010 09:09:50 -0400, Ty Ford
wrote:

Somebody didn't get some last night

Unwarranted, mean spirited and not to the point.

Yup. That sounds like Usenet :-)

[Danny T]

On May 27, 8:42*am, (Scott Dorsey) wrote:
Danny T wrote:



Hey Scott, I'm not actually worried about anything - frankly, this
stuff is cheap and I've spent more on a night's worth of beer :-) *I
just had some questions about why because things didn't add up right
in my head. I started thinking about how specs were written and didn't
want to believe that companies would stretch things like they do.

Because companies make cheap junk. *Everybody wants their headphones to be
more efficient and run off lower voltage rails, so they go to lower and
lower impedance. *But everybody wants their output sections to cost less,
so they skimp on current drive.

The end result is that if you get a real headphone amp, your headphones will
probably have flatter response than if you plug them into the headphone output
of a bargain-basement mixer.
--scott

--
"C'est un Nagra. *C'est suisse, et tres, tres precis."

I don't know that I even know of a good head phone amp. All I've ever
seen are cheap ones. Actually, I think my attitude toward headphones
has been that they don't really matter much so long as what goes in
the mic it good. I think I am changing my mind as of late but I don't
really think there is such a good thing as great sounding headphones.
They never sound like speakers so I might say what's the point?

[Danny T]

On May 27, 7:04*am, "geoff" wrote:
Danny T wrote:
It seems to me that most headphone amps need at least 100 ohms - I
have 3 and they are rated at no less then 100 ohms....

Sony 7506's seem to be listed at 63 ohms so why would that be? I must
be misunderstanding a relationship or something because I cannot see
why/how that would be the case for one of the more popular headsets (I
have 4).

My AKG K240's say they are 600 ohms. I have some really old phones
that list 600 ohms as well.

Any thoughts on this ?

The newer ones are all around 55 Ohms. *Run a resistor ( two) in series and
turn the volume up to compensate.

geoff

I bought a stack of phones from Federated in Los Angeles when they
went out of business (I know - I'm dated now). I can't remember who
made them and the name has long since rubbed off of all of them. They
were big, gray hard shell cans, had a mono switch on them and L/R on
off too. They don't sound wonderful but they are good and the best
part is that they have the least bleed through I've ever had on
headphones. I bought them when they store was down to the 10% of cost
level and I think I paid something in the $20 ish range. I have no
idea why I'm rambling about them but I do have a sort of love affair
going with them. they live in a nice metal case and I don't use them
much because I want to save them for something - I think :-)

[Mike Rivers]

Danny T wrote:

I don't know that I even know of a good head phone amp. All I've ever
seen are cheap ones.

Aphex has a pretty good one, the HeadPod, that doesn't cost
to many arms and legs. You might find the graph of output
power vs. headphone impedance to be educational. Also, note
that the warning "CAUTION - TURN DOWN VOLUME BEFORE PLUGGING
IN" is printed right on the front panel. But then I guess
nobody reads instructions on how to pour **** out of a boot
either.

http://www.aphex.com/454.htm

Actually, I think my attitude toward headphones
has been that they don't really matter much so long as what goes in
the mic it good. nd like speakers so I might say what's the point?

With decent headphones, you can tell if what's going into
the mic is good. With poor headphones, you can't always tell
if it's in the best place or even if it's the best mic
(among what you have available) for the job.


--
"Today's production equipment is IT based and cannot be
operated without a passing knowledge of computing, although
it seems that it can be operated without a passing knowledge
of audio." - John Watkinson

[Laurence Payne[_2_]]

On Thu, 27 May 2010 09:18:35 -0700 (PDT), Danny T
wrote:

I don't know that I even know of a good head phone amp. All I've ever
seen are cheap ones. Actually, I think my attitude toward headphones
has been that they don't really matter much so long as what goes in
the mic it good. I think I am changing my mind as of late but I don't
really think there is such a good thing as great sounding headphones.
They never sound like speakers so I might say what's the point?

But speakers never sound like other speakers, and never sound like the
source. It's never going to be right. But it might sound good.

[[email protected]]

On Thu, 27 May 2010 02:39:02 +0000 (UTC), wrote:


On 2010-05-26 said:
There's already a device for that. It's called the volume
control.
very funny...
My ex was a radio announcer at one time, and one day she came home
with an ear ache. Seems the asshole at the controls found a way to
put 130db or so into her phones for a few seconds, (till she ripped
them off), making it some what uncomfortable to finish her shift.
The industry needs limited head phone amplifiers. (not just volume
controls.).

IF I'm feeding people other than myself program via
headphones or in-ear there's always limiters in the chain.
I won't be responsible for damaging somebody else's hearing
because of a screwup somewhere. YEs I'm going to be minding
the volume controls, but in a live situation I can't always
be sure something stupid might not occur.

I for one refuse to 'try' other peoples headphones, they usually
want to turn them up loud.

CAn understand that. I hate to use them even while working
ham radio on the hf bands because about the time I get a
comfortable listening level of a weak station some yokel
while dump in a carier enough off frequency that he gives me
1.5 khz or something else neat and the agc on my receiver
can't knock it down in time for it not to be painful. I'll
put 'em on if I"m trying to work a weak radio op aboard a
vessel at sea who might have an emergency or something like
that, but otherwise ...

My lady otoh won't run a net on hf without using them.


Phones are good for picking out the low level signals, but man can be dangerous!
I always listen with a squint!

I designed a PA system for a club in the 70s, and I had to build a headphone amp
for the DJ. I used an op amp which would drive his phones, and to finalize the
design, I fed it completely clipped signal at full output, and put a resistor
pad that limited the volume to an acceptable level. It was quite loud because it
was the DJ's booth and he needed some volume, but it wouldn't go as far as pain
threshold.